1. Field of the Disclosure
The present disclosure relates to an optical line terminal and an optical network unit that have a function of saving power of a device by stopping operation of partial functions for a predetermined period in an optical network that performs point-to-point or point-to-multi-point communication.
2. Discussion of the Background Art
As illustrated in FIG. 1, an optical network is a network in which one optical line terminal (OLT) performs point-to-point communication with one optical network unit (ONU) through an optical fiber transmission path.
As illustrated in FIG. 2, a passive optical network (PON) is a network in which one optical line terminal (OLT) performs point-to-multi-point communication with plural optical network units (ONU) through an optical fiber transmission path and a one-to-n optical splitter (n refers to a natural number). As a representative standard of a gigabit-class PON, an Ethernet (registered trademark) PON (EPON) that is standardized in the IEEE802.3 is known. In addition, a 10G-EPON is examined as a 10 gigabit-class PON in the IEEE802.3av examination group.
FIG. 3 is a functional block diagram of a conventional OLT in an EPON. A downlink main signal is transmitted to a PON interface (PON-IF) port 101 through a service node interface (SNI) port 104, a queue managing unit 103, and a PON signal processing unit 102. Meanwhile, an uplink main signal is transmitted to the SNI port 104 through the PON-IF port 101, the PON signal processing unit 102, and the queue managing unit 103. An OLT 100 has a multi-point control protocol (MPCP) unit that reports a data amount in a queue included in the ONU to the ONU using a report message, a band allocating unit that monitors the data amount in the queue included in the ONU on the basis of the report message received from the ONU and allocates an instantaneous bandwidth under use to each ONU, and an operations, administration, and maintenance (OAM) unit that exchanges a control frame for maintenance and monitor with the ONU, as the PON signal processing unit 102.
FIG. 4 is a functional block diagram of a conventional ONU in an EPON. An uplink main signal is transmitted to a PON-IF port 204 through a user network interface (UNI) port 201, a queue managing unit 202, and a PON signal processing unit 203. Meanwhile, a downlink main signal is transmitted to the UNI port 201 through the PON-IF port 204, the PON signal processing unit 203, and the queue managing unit 202. The ONU 200 has an MPCP unit that reports a data amount in a queue to the OLT and an OAM unit that exchanges a control frame for maintenance and monitor with the OLT, as the PON signal processing unit 203.
As a conventional technology that is related to saving of power of a communication terminal, a method that causes a transmitting terminal to monitor a flow control signal from a receiving terminal and perform power saving control is described in Patent Document 1.
FIG. 15 is a diagram illustrating the configuration of an optical network system of a point-to-point type. An optical network of the point-to-point type is a network in which one optical line terminal (OLT) 73 performs one-to-one communication with one optical network unit (ONU) 71 through an optical fiber transmission path 72.
FIG. 16 is a diagram illustrating the configuration of a passive optical network (PON) system of a point-to-multi-point type. The PON is a network in which one optical line terminal (OLT) 830 performs one-to-n communication with plural optical network units (ONU) 81 to 8n through an optical fiber transmission path 820 and a one-to-n (n refers to a natural number) optical splitter 810. As a representative standard of a gigabit-class PON, an Ethernet (registered trademark) PON (EPON) that is standardized in the IEEE802.3 is known.
FIG. 17 is a diagram illustrating the configuration of a conventional OLT in an EPON. An OLT 90 includes a PON interface (PON-IF) 91, a PON signal processing unit 92, a queue managing unit 93, and a service node interface (SNI) 94.
The PON-IF 91 is an interface that is used to connect the OLT and the optical network.
The PON signal processing unit 92 includes a multi-point control protocol (MPCP) module 95, a band allocating module 96, an operations, administration, and maintenance (OAM) module 97, a media access control (MAC) module 98, and a physical layer (PHY) module 99.
The MPCP module 95 reports a data amount in a queue included in the ONU to the ONU using a report message. The band allocating module 96 monitors the data amount in the queue included in the ONU on the basis of the report message received from the ONU and allocates an instantaneous bandwidth under use to each ONU. The OAM module 97 exchanges a control frame for maintenance and monitor with the ONU. The MAC module 98 controls a transmitting/receiving operation of an MAC frame. The PHY module 99 that is a physical layer performs signal conversion between a signal having a MAC frame format and a signal transmitted through the optical network.
The queue managing unit 93 queues data that is exchanged with a service network and manages the data.
The SNI 94 is an interface that is used to connect the OLT and the service network.
A downlink main signal is transmitted to the PON-IF 91 through the SNI 94, the queue managing unit 93, and the PON signal processing unit 92. Meanwhile, an uplink main signal is transmitted to the SNI 94 through the PON-IF 91, the PON signal processing unit 92, and the queue managing unit 93.
FIG. 18 is a diagram illustrating the configuration of a conventional ONU in an EPON. An ONU 100 includes a user network interface (UNI) 101, a queue managing unit 102, a PON signal processing unit 103, and a PON-IF 104.
The UNI 101 is an interface that is used to connect the ONU and a terminal such as a PC or a router.
The queue managing unit 102 queues data that is exchanged with the terminal and manages the data.
The PON signal processing unit 103 includes an MPCP module 105, an OAM module 106, a MAC module 107, and a PHY module 108.
The MPCP module 105 reports a data amount in a queue to the OLT using a report message. The OAM module 106 exchanges a control frame for maintenance and monitor with the OLT. The MAC module 107 controls a transmitting/receiving operation of a MAC frame. The PHY module 108 that is a physical layer performs signal conversion between a signal having a MAC frame format and a signal transmitted through the optical network.
The PON-IF 104 is an interface that is used to connect the ONU and the optical network.
An uplink main signal is transmitted to the PON-IF 104 through the UNI 101, the queue managing unit 102, and the PON signal processing unit 103. Meanwhile, a downlink main signal is transmitted to the UNI 101 through the PON-IF 104, the PON signal processing unit 103, and the queue managing unit 102.
In the IEEE802.3av taskforce, 10G-EPON is examined as a 10 gigabit-class PON. Meanwhile, as a technology for saving power of a communication device, mounting of a sleep method that stops non-used functions in the case where communication in a non-communication state (idle state) or an adaptive link rate method that changes a link rate according to a communication amount is examined (for example, refer to Non-patent Document 2).
In addition, in the IEEE802.3az taskforce, standardization of the power-saving Ethernet (registered trademark) is advanced. As the conventional technology that is related to saving of power of a communication terminal, a method that causes a transmitting terminal to monitor a flow control signal from a receiving terminal and perform power saving control is known (for example, refer to Patent Document 1).
FIG. 19 is a diagram illustrating an autonomous intermittent start method that is an example of the sleep method in two facing communication devices.
A second communication device 112 monitors traffic that is transmitted from a first communication device 111 to the second communication device 112 or from the second communication device 112 to the first communication device 111. Further, it sets threshold values for an arrival interval of transmission frames, an instantaneous bandwidth under use, or a queue length in a buffer, and when it exceeds the threshold values, it is determined to be in a non-communication state. When it is determined to be in the non-communication state, it transmits a sleep request message to the first communication device 111 and stops partial functions of the second communication device 112.
When the second communication device 112 starts up, it communicates with the first communication device 111 (S1102). If the first communication device 111 receives a sleep request from the second communication device 112 (S1103), it transmits a confirmation response (ACK message) to the second communication device 112 (S1104). If the second communication device 112 receives the confirmation response, it stops the partial functions for a predetermined period (S1105).
The second communication device 112 restarts after a predetermined time passes (S1106), confirms existence or non-existence of the traffic with respect to the communication device 1101 (traffic confirmation message) (S1107), and when it is in the non-communication state (NO message) (S1108), it stops the partial functions for a predetermined period (S1109). Further, it restarts after the predetermined time passes (S1110), confirms existence or non-existence of the traffic with respect to the first communication device 111 (S1111), and when frames arrive (YES message) (S1112), it restarts communication with the first communication device 111 (S1113). Hereinafter, the same operation is executed for S1114 to S1124.
The autonomous intermittent start method can be applied to a network of a point-to-point type topology and a point-to-multi-point type topology. For example, in the case of the EPON, power of the ONU can be saved by associating the first communication device 111 with the OLT and associating the second communication device 112 with the ONU.
FIG. 28 is a diagram illustrating the configuration of an optical network system of a point-to-point type. An optical network of a point-to-point type is a network in which one optical line terminal (OLT) 93 performs one-to-one communication with one optical network unit (ONU) 91 through an optical fiber transmission path 92.
FIG. 29 is a diagram illustrating the configuration of a passive optical network (PON) system of a point-to-multi-point type. The PON is a network in which one optical line terminal (OLT) 1030 performs 1-to-n communication with plural optical network units (ONU) 101 to 10n through an optical fiber transmission path 1020 and a one-to-n (n refers to a natural number) optical splitter 1010. As a representative standard of a gigabit-class PON, an Ethernet (registered trademark) PON (EPON) that is standardized in the IEEE802.3 is known.
FIG. 30 is a diagram illustrating the configuration of a conventional OLT in an EPON. An OLT 110 includes a PON interface (PON-IF) 111, a PON signal processing unit 112, a queue managing unit 113, and a service node interface (SNI) 114.
The PON-IF 111 is an interface that is used to connect the OLT 110 and an optical network.
The PON signal processing unit 112 includes a multi-point control protocol (MPCP) module 115, a band allocating module 116, an operations, administration, and maintenance (OAM) module 117, a media access control (MAC) module 118, and a physical layer (PHY) module 119.
The MPCP module 115 reports a data amount in a queue included in the ONU to the ONU using a report message. The band allocating module 116 monitors the data amount in the queue included in the ONU, on the basis of the report message received from the ONU, and allocates an instantaneous bandwidth under use to each ONU. The OAM module 117 exchanges a control frame for maintenance and monitor with the ONU. The MAC module 118 controls a transmitting/receiving operation of a MAC frame. The PHY module 119 that is a physical layer performs signal conversion between a signal having a MAC frame format and a signal transmitted through the optical network.
The queue managing unit 113 queues data that is exchanged with a service network and manages the data.
The SNI 114 is an interface that is used to connect the OLT and the service network.
A downlink main signal is transmitted to the PON-IF 111 through the SNI 114, the queue managing unit 113, and the PON signal processing unit 112. Meanwhile, an uplink main signal is transmitted to the SNI 114 through the PON-IF 111, the PON signal processing unit 112, and the queue managing unit 113.
FIG. 31 is a diagram illustrating the configuration of a conventional ONU in an EPON. An ONU 120 includes a user network interface (UNI) 121, a queue managing unit 122, a PON signal processing unit 123, and a PON-IF 124.
The UNI 121 is an interface that is used to connect the ONU 120 and a terminal such as a PC or a router.
The queue managing unit 122 queues data that is exchanged with the terminal and manages the data.
The PON signal processing unit 123 includes an MPCP module 125, an OAM module 126, a MAC module 127, and a PHY module 128.
The MPCP module 125 reports a data amount in a queue to the OLT using a report message. The OAM module 126 exchanges a control frame for maintenance and monitor with the OLT. The MAC module 127 controls a transmitting/receiving operation of a MAC frame. The PHY module 128 that is a physical layer performs signal conversion between a signal having a MAC frame format and a signal transmitted through the optical network.
The PON-IF 124 is an interface that is used to connect the ONU and the optical network.
An uplink main signal is transmitted to the PON-IF 124 through the UNI 121, the queue managing unit 122 and the PON signal processing unit 123. Meanwhile, a downlink main signal is transmitted to the UNI 121 through the PON-IF 124, the PON signal processing unit 123, and the queue managing unit 122.
In the IEEE802.3av taskforce, 10G-EPON is examined as a 10 gigabit-class PON. Meanwhile, as a technology for saving power of a communication device, mounting of a sleep method that stops non-used functions in the case where communication is in a non-communication state (idle state) or an adaptive link rate method that changes a link rate according to a communication amount is examined (for example, refer to Non-patent Document 2).
In addition, in the IEEE802.3az taskforce, standardization of the power-saving Ethernet (registered trademark) is being progressed. As the conventional technology that is related to saving of power of a communication terminal, a method that causes a transmitting terminal to monitor a flow control signal from a receiving terminal and perform power saving control is known (for example, refer to Patent Document 1).
FIG. 32 is a diagram illustrating a master/slave type intermittent start method as an example of the sleep method in two facing communication devices.
A first communication device 131 monitors traffic that is transmitted from the first communication device 131 to a second communication device 132 or from the second communication device 132 to the first communication device 131. Further, it sets threshold values for an arrival interval of transmission frames, an instantaneous bandwidth under use, or a queue length in a buffer, and when it exceeds the threshold values, it is determined to be in a non-communication state. When it is determined to be in the non-communication state, it transmits a sleep instruction message to the second communication device 132 and stops partial functions of the second communication device 132.
When the second communication device 132 starts up (S1301), it communicates with the first communication device 131 (S1302). If the second communication device 132 receives a sleep instruction from the first communication device 131 (S1303), it transmits a confirmation response (ACK message) to the first communication device 131 (S1304). Then, the second communication device 132 stops the partial functions for a predetermined period (S1305).
The second communication device 132 restarts after a predetermined time passes (S1306), confirms existence or non-existence of the traffic with respect to the first communication device 131 (traffic confirmation message) (S1307), and when it is in the non-communication state (NO message) (S1308), stops the partial functions for a predetermined period (S1309). Further, it restarts after the predetermined time passes (S1310), confirms existence or non-existence of the traffic with respect to the first communication device 131 (S1311), and when frames arrive (YES message) (S1312), restarts communication with the first communication device 131 (S1313). Hereinafter, the same operation is executed for S1314 to S1324.
The master/slave type intermittent start method can be applied to a network of a point-to-point type topology and a point-to-multi-point type topology. For example, in the case of the EPON, power of the ONU can be saved by associating the first communication device 131 with the OLT and associating the second communication device 132 with the ONU.
FIG. 33 is a diagram illustrating the configuration of an optical network system of a point-to-point type. An optical network of a point-to-point type is a network in which one optical line terminal (OLT) 13 performs one-to-one communication with one optical network unit (ONU) 11 through an optical fiber transmission path 12.
FIG. 34 is a diagram illustrating the configuration of a passive optical network (PON) system of a point-to-multi-point type. The PON is a network in which one optical line terminal (OLT) 230 performs 1-to-n communication with plural optical network units (ONU) 21 to 2n through an optical fiber transmission path 220 and a one-to-n (n refers to a natural number) optical splitter 210. As a representative standard of a gigabit-class PON, an Ethernet (registered trademark) PON (EPON) that is standardized in the IEEE802.3 is known.
FIG. 35 is a diagram illustrating the configuration of a conventional OLT in an EPON. An OLT 30 includes a PON interface (PON-IF) 31, a PON signal processing unit 32, a queue managing unit 33, and a service node interface (SNI) 34. The PON-IF 31 is an interface that is used to connect the OLT and an optical network.
The PON signal processing unit 32 includes a multi-point control protocol (MPCP) module 35, a band allocating module 36, an operations, administration, and maintenance (OAM) module 37, a media access control (MAC) module 38, and a physical layer (PHY) module 39.
The MPCP module 35 reports a data amount in a queue included in the ONU to the ONU using a report message. The band allocating module 36 monitors the data amount in the queue in the ONU, on the basis of the report message received from the ONU, and allocates an instantaneous bandwidth under use to each ONU. The OAM module 37 exchanges a control frame for maintenance and monitor with the ONU. The MAC module 38 controls a transmitting/receiving operation of a MAC frame. The PHY module 39 that is a physical layer performs signal conversion between a signal having a MAC frame format and a signal transmitted through the optical network.
The queue managing unit 33 queues data that is exchanged with a service network and manages the data. The SNI 34 is an interface that is used to connect the OLT and the service network. A downlink main signal is transmitted to the PON-IF 31 through the SNI 34, the queue managing unit 33, and the PON signal processing unit 32. Meanwhile, an uplink main signal is transmitted to the SNI 34 through the PON-IF 31, the PON signal processing unit 32, and the queue managing unit 33.
FIG. 36 is a diagram illustrating the configuration of a conventional ONU in an EPON. An ONU 40 includes a user network interface (UNI) 41, a queue managing unit 42, a PON signal processing unit 43, and a PON-IF 44.
The UNI 41 is an interface that is used to connect the ONU and a terminal such as a PC or a router. The queue managing unit 42 queues data that is exchanged with the terminal and manages the data. The PON signal processing unit 43 includes an MPCP module 45, an OAM module 46, a MAC module 47, and a PHY module 48.
The MPCP module 45 reports a data amount in a queue to the OLT using a report message. The OAM module 46 exchanges a control frame for maintenance and monitor with the OLT. The MAC module 47 controls a transmitting/receiving operation of a MAC frame. The PHY module 48 that is a physical layer performs signal conversion between a signal having a MAC frame format and a signal transmitted through the optical network. The PON-IF 44 is an interface that is used to connect the ONU and the optical network.
An uplink main signal is transmitted to the PON-IF 44 through the UNI 41, the queue managing unit 42 and the PON signal processing unit 43. Meanwhile, a downlink main signal is transmitted to the UNI 41 through the PON-IF 44, the PON signal processing unit 43, and the queue managing unit 42.
In the IEEE802.3av taskforce, 10G-EPON is examined as a 10 gigabit-class PON. Meanwhile, as a technology for saving power of a communication device, mounting of a sleep method that stops non-used functions in the case where communication is in a non-communication state (idle state) or an adaptive link rate method that changes a link rate according to a communication amount is examined (for example, refer to Non-patent Document 2).
In addition, in the IEEE802.3az taskforce, standardization of the power-saving Ethernet (registered trademark) is being progressed. As the conventional technology that is related to saving of power of a communication terminal, a method that causes a transmitting terminal to monitor a flow control signal from a receiving terminal and perform power saving control is known (for example, refer to Patent Document 1).
FIG. 37 is a diagram illustrating an autonomous intermittent start method as an example of the sleep method in two facing communication devices.
A second communication device 52 monitors traffic that is transmitted from a first communication device 51 to the second communication device 52 or from the second communication device 52 to the first communication device 51. Further, it sets threshold values for an arrival interval of transmission frames, an instantaneous bandwidth under use, or a queue length in a buffer, and when it exceeds the threshold values, it is determined to be in a non-communication state. When it is determined to be in the non-communication state, it transmits a sleep request message to the first communication device 51 and stops partial functions of the second communication device 52.
When the second communication device 52 starts up (step S501), it communicates with the first communication device 51 (S502). If the first communication device 51 receives a sleep request from the second communication device 52 (S503), it transmits a confirmation response (ACK message) to the second communication device 52 (S504). If the second communication device 52 receives the confirmation response, it stops the partial functions for a predetermined period (S505).
The second communication device 52 restarts after a predetermined time passes (S506), confirms existence or non-existence of the traffic with respect to the first communication device 51 (traffic confirmation message) (S507), and when it is in the non-communication state (NO message) (S508), stops the partial functions for a predetermined period (S509). Further, it restarts after the predetermined period passes (S510), confirms existence or non-existence of the traffic with respect to the first communication device 51 (S511), and when frames arrive (YES message) (S512), restarts communication with the first communication device 51 (S513). Hereinafter, the same operation is executed for S514 to S524.
The autonomous intermittent start method can be applied to a network of a point-to-point type topology and a point-to-multi-point type topology. For example, in the case of the EPON, power of the ONU can be saved by associating the first communication device 51 with the OLT and associating the second communication device 52 with the ONU.
FIG. 38 is a diagram illustrating a master/slave type intermittent start method as an example of the sleep method in two facing communication devices.
A third communication device 61 monitors traffic that is transmitted from the third communication device 61 to a fourth communication device 62 or from the fourth communication device 62 to the third communication device 61. Further, it sets threshold values for an arrival interval of transmission frames, an instantaneous bandwidth under use, or a queue length in a buffer, and when it exceeds the threshold values, it is determined to be in a non-communication state. When it is determined to be in the non-communication state, it transmits a sleep instruction message to the fourth communication device 62 and stops partial functions of the fourth communication device 62.
When the fourth communication device 62 starts up (S601), it communicates with the third communication device 61 (S602). If the fourth communication device 62 receives a sleep instruction from the third communication device 61 (S603), it transmits a confirmation response (ACK message) to the third communication device 61 (S604). Then, the fourth communication device 62 stops partial functions for a predetermined period (S605).
The fourth communication device 62 restarts after the predetermined time passes (S606), confirms existence or non-existence of the traffic with respect to the third communication device 61 (traffic confirmation message) (S607), and when it is in the non-communication state (NO message) (S608), stops the partial functions for a predetermined period (S609). Further, it restarts after the predetermined period passes (S610), confirms existence or non-existence of the traffic with respect to the third communication device 61 (S611), and when frames arrive (YES message) (S612), restarts communication with the third communication device 61 (S613). Hereinafter, the same operation is executed for S614 to S624.
The master/slave type intermittent start method can be applied to a network of a point-to-point type topology and a point-to-multi-point type topology. For example, in the case of the EPON, power of the ONU can be saved by associating the third communication device 61 with the OLT and associating the fourth communication device 62 with the ONU.    Patent Document 1: Japanese Patent Application Laid-Open No. 2008-263281Non-Patent Document    Non-patent Document 1: Tsutomu Tatsuta, Noriyuki Oota, Noriki Miki, and Kiyomi Kumozaki, “Design philosophy and performance of a GE-PON system for mass deployment”, JOURNAL OF OPTICAL NETWORKING, Vol. 6, No. 6, June 2007.    Non-patent Document 2: Sergiu Nedevschi, Lucian Popa, Gianluca Iannaccone, Sylvia Ratnasamy, David Wetherall, “Reducing network energy consumption via sleeping and rate-adaptation”, Proceedings of the 5th USENIX Symposium on Networked Systems Design and Implementation, pp. 323-336, 2008.
However, in the PON that performs the point-to-multi-point communication through the optical splitter, the signal that is transmitted from the OLT may be physically broadcast to all ONUs. For this reason, only the specific ONU cannot be returned from the sleep state with ON/OFF of a physical signal as a trigger, and the other ONUs that enter into the sleep state may be returned from the sleep state. As a result, there has been a problem in that an increase in consumption power of the entire optical network may be caused by connecting the plural ONUs in the non-communication state. Further, even in the optical network that performs the point-to-point communication, there has been a problem in that a receiving unit of the ONU cannot be completely stopped to return the ONU from the sleep state with ON/OFF of the physical signal as the trigger.